The invention relates to a reducer coupling useful for connecting conduit sections of different sizes, and a positioner tool for moving the coupling into a desired position for making the connection. The positioner tool also provides a means for turning the reducer coupling to thread it into a conduit section.
There are many industrial operations in which a reducer coupling is used as a connection for joining two conduit sections of different sizes. The usual conduit connections are those where two sections of pipe are connected, or a pipe is connected to a valve connection, or a pipe is connected to a pump, or the like. For example, in oil field operations such as well stimulation and completion, it is common practice to use fittings known as swage nipples to connect the production casing with smaller piping. In these operations fluids are delivered from the smaller piping, usually under high pressure, through the nipple and into the production casing. To set up for such an operation, the usual procedure is to first lift the fitting into a "hook-up" position above the production casing. The large end of the nipple is then threaded into the production casing and turned down tight with a strap wrench, which fastens around the nipple just below the small end. Following this, the small end is connected into the delivery pipe with a conventional union fitting.
Swage nipples now in use have several drawbacks, which make them less than satisfactory for the operations described above and for other commercial applications. One problem is that swage nipples are structurally weak, particularly at the point where the wrench clamps around the fitting. The weakness is caused by severe deformation of the construction material during fabrication of the fitting. As the strap wrench is tightened on the nipple, it tends to slip and score the metal surface, causing further weakness at this point on the fitting. This weakness is particularly undesirable because of the high pressure conditions the fitting must endure during normal use.
The structural weakness of swage nipples, plus the fact that the small end of each fitting defines a "neck" portion, creates another problem. Sometimes, particularly after an operation is completed, the fittings are dropped or otherwise mis-handled. Frequently, such treatment causes the neck of the fitting to break off, so that it must be repaired or replaced for the next operation. This is both costly and inconvenient. The reducer coupling of this invention avoids the problems described above and it is much cheaper to make than the swage nipples now available. For example, the present reducer coupling is a one-piece structure which can be easily lifted into the "hook-up" position described above, and coupled to the production casing using a tool designed for that purpose. In addition, the present coupling is a much more durable structure than the prior swage nipples, and the smaller end of the fitting has a hub connection which is protected from breaking off, or sustaining other damage during handling of the fitting.